Last Friday, EPA published notice that it would not be revising its regulations on backup generators in response to three petitions for reconsideration it had received after it promulgated its final rule in January 2013. The rule had sparked controversy, because EPA allowed backup generators to operate for up to 100 hours a year, though EPA did require use of ultra-low sulfur diesel fuel beginning in January 2015.

There were three major issues in the petitions. EPA’s responses addressed them as follows:

• The timing of the requirement to utilize ULSD. EPA rejected arguments that ULSD is already sufficiently available to require its use immediately.

• The timing and required information for reporting with respect to emergency engines. EPA rejected the request to move up the reporting, finding that it would be unduly burdensome.

• Criteria for operation in non-emergency situations. EPA rejected arguments that its criteria for allowing such operation were “too indistinct and expansive.”

As we had previously noted, EPA had a difficult balancing act here. It has clearly concluded that, with use of ULSD, backup engines provide sufficient benefit in assisting demand response – the very purpose of which is to reduce emissions by substituting reduced demand for increased supply – to warrant allowing increased use of these otherwise less efficient engines.